Middle or large-sized battery module

ABSTRACT

Disclosed herein is a middle- or large-sized battery module comprising: a battery cell stack including a plurality of battery cells or unit modules electrically connected with each other; a first module case constructed in a structure to entirely surround one side end of the battery cell stack and to partially surround the upper and lower ends of the battery cell stack; a second module case coupled with the first module case, the second module case being constructed in a structure to entirely surround the other side end of the battery cell stack and to partially surround the upper and lower ends of the battery cell stack; a sensing member mounted to the first module case or the second module case; and a battery management system (BMS) mounted to the first module case or the second module case.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 12/986,426, filed Jan. 7, 2011, which is a continuation of U.S.application Ser. No. 12/224,688 filed Apr. 10, 2009, now U.S. Pat. No.7,892,669, which is a national phase entry under 35 U.S.C. §371 ofInternational Application No. PCT/KR2007/001017 filed Feb. 28, 2007,published in English, which claims priority from Korean PatentApplication Nos. 10-2006-0020772, filed Mar. 6, 2006 and10-2006-0045443, filed May 22, 2006, the disclosures of which areincorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to a middle- or large-sized batterymodule, and, more particularly, to a middle- or large-sized batterymodule comprising: a battery cell stack including a plurality of batterycells or unit modules electrically connected with each other, thebattery cells or unit modules being erected in the lateral direction; afirst module case constructed in a structure to entirely surround oneside end of the battery cell stack and to partially surround the upperand lower ends of the battery cell stack, the first module case beingprovided at the front part thereof with external input and outputterminals; a second module case coupled with the first module case, thesecond module case being constructed in a structure to entirely surroundthe other side end of the battery cell stack and to partially surroundthe upper and lower ends of the battery cell stack, the second modulecase being provided at the front part thereof with bus bars forconnecting electrode terminals of the battery cell stack to the externalinput and output terminals; a sensing member mounted to the first modulecase or the second module case; and a battery management system (BMS)mounted to the first module case or the second module case, while beingconnected to the sensing member, for monitoring and controlling theoperation of the battery module.

BACKGROUND OF THE INVENTION

Recently, a secondary battery, which can be charged and discharged, hasbeen widely used as an energy source for wireless mobile devices. Also,the secondary battery has attracted considerable attention as an energysource for electric vehicles (EV) and hybrid electric vehicles (HEV),which have been developed to solve problems, such as air pollution,caused by existing gasoline and diesel vehicles using fossil fuel.

Small-sized mobile devices use one or several small-sized battery cellsfor each device. On the other hand, middle- or large-sized devices, suchas vehicles, use a middle- or large-sized battery module having aplurality of battery cells electrically connected with each otherbecause high output and large capacity are necessary for the middle- orlarge-sized devices.

Preferably, the middle- or large-sized battery module is manufacturedwith small size and small weight if possible. For this reason, aprismatic battery or a pouch-shaped battery, which can be stacked withhigh integration and has a small weight to capacity ratio, is usuallyused as a battery cell of the middle- or large-sized battery module.Especially, much interest is currently generated in the pouch-shapedbattery, which uses an aluminum laminate sheet as a sheathing member,because the weight of the pouch-shaped battery is small and themanufacturing costs of the pouch-shaped battery are low.

FIG. 1 is a perspective view typically illustrating a conventionalrepresentative pouch-shaped battery. The pouch-shaped battery 100 shownin FIG. 1 is constructed in a structure in which two electrode leads 110and 120 protrude from the upper and lower ends of a battery body 130,respectively, while the electrode leads 110 and 120 are opposite to eachother. A sheathing member 140 comprises upper and lower sheathing parts.That is, the sheathing member 140 is a two-unit member. An electrodeassembly (not shown) is received in a receiving part which is definedbetween the upper and lower sheathing parts of the sheathing member 140.The opposite sides 140 a and the upper and lower ends 140 b and 140 c,which are contact regions of the upper and lower sheathing parts of thesheathing member 140, are bonded to each other, whereby the pouch-shapedbattery 100 is manufactured. The sheathing member 140 is constructed ina laminate structure of a resin layer/a metal film layer/a resin layer.Consequently, it is possible to bond the opposite sides 140 a and theupper and lower ends 140 b and 140 c of the upper and lower sheathingparts of the sheathing member 140, which are in contact with each other,to each other by applying heat and pressure to the opposite sides 140 aand the upper and lower ends 140 b and 140 c of the upper and lowersheathing parts of the sheathing member 140 so as to weld the resinlayers thereof to each other. According to circumstances, the oppositesides 140 a and the upper and lower ends 140 b and 140 c of the upperand lower sheathing parts of the sheathing member 140 may be bonded toeach other using a bonding agent. For the opposite sides 140 a of thesheathing member 140, the same resin layers of the upper and lowersheathing parts of the sheathing member 140 are in direct contact witheach other, whereby uniform sealing at the opposite sides 140 a of thesheathing member 140 is accomplished by welding. For the upper and lowerends 140 b and 140 c of the sheathing member 140, on the other hand, theelectrode leads 110 and 120 protrude from the upper and lower ends 140 band 140 c of the sheathing member 140, respectively. For this reason,the upper and lower ends 140 b and 140 c of the upper and lowersheathing parts of the sheathing member 140 are thermally welded to eachother, while a film-shaped sealing member 160 is interposed between theelectrode leads 110 and 120 and the sheathing member 140, inconsideration of the thickness of the electrode leads 110 and 120 andthe difference in material between the electrode leads 110 and 120 andthe sheathing member 140, so as to increase sealability of the sheathingmember 140.

However, the mechanical strength of the sheathing member 140 is low. Inorder to solve this problem, there has been proposed a method ofmounting battery cells (unit cells) in a pack case, such as a cartridge,so as to manufacture a battery module having a stable structure.However, a device or a vehicle, in which a middle- or large-sizedbattery module is installed, has a limited installation space.Consequently, when the size of the battery module is increased due tothe use of the pack case, such as the cartridge, the spatial utilizationis lowered. Also, due to the low mechanical strength, the battery cellsrepeatedly expand and contract during the charge and the discharge ofthe battery cells. As a result, the thermally welded regions of thesheathing member may be easily separated from each other.

Also, when a middle- or large-sized battery module is constructed usinga plurality of battery cells or a plurality of unit modules each ofwhich includes a predetermined number of battery cells, a plurality ofmembers for mechanical coupling and electrical connection between thebattery cells or the unit modules are needed, and a process forassembling the mechanical coupling and electrical connection members isvery complicated. Furthermore, there is needed a space for coupling,welding, or soldering the mechanical coupling and electrical connectionmembers with the result that the total size of the system is increased.The increase in size of the system is not preferred in consideration ofthe spatial limit of an apparatus or device in which the middle- orlarge-sized battery module is mounted.

In this connection, there have been proposed several middle- orlarge-sized battery modules manufactured by simplified assemblyprocesses. For example, Japanese Patent Application Publication No.2005-209365 discloses a battery module including a center frame to whichbattery cells are individually mounted and terminal-side and bottom-sideframes coupled respectively to the lower and upper ends of the centerframe while the battery cells are mounted to the center frame. Thedisclosed battery module has an advantage in that the assembly of thebattery module is easy. However, only the central parts of the batterycells are fixed to the center frame with the result that it is difficultto restrain the contraction and expansion of the battery cells duringthe repetitive charge and discharge of the battery cells, and therefore,it is limited to use pouch-shaped battery cells without modifying thebattery cells. In addition, there is needed a process for connectingelectrode terminals of the battery cells to a circuit board so as toaccomplish the electrical connection between the battery cells.Furthermore, the size of the battery module is inevitably increased dueto the provision of the center frame.

Also, Japanese Patent Application Publication No. 2003-123721 disclosesa battery module constructed in a structure in which a prismatic batterycell stack is fixed to an upper-side case, a lower-side case, and a pairof end plates. However, the disclosed battery module has severalproblems in that the battery cells are fixed while being in tightcontact with each other with the result that the heat dissipation is noteasily accomplished, it is structurally difficult to use pouch-shapedbattery cells in the battery module, and an additional member forinterconnecting the end plates is needed.

Meanwhile, since a battery module is a structural body including aplurality of battery cells which are combined with each other, thesafety and the operating efficiency of the battery module are loweredwhen overvoltage, overcurrent, and overheat occurs in some of thebattery cells. Consequently, a sensing unit for sensing the overvoltage,overcurrent, and overheat are needed. Specifically, voltage andtemperature sensors are connected to the battery cells so as to senseand control the operation of the battery cells in real time or atpredetermined time intervals. However, the attachment or the connectionof the sensing unit complicates the assembly process of the batterymodule. In addition, short circuits may occur due to the provision of aplurality of wires necessary for the attachment or the connection of thesensing unit.

Consequently, there is high necessity for a middle- or large-sizedbattery module that is compact and structurally stable, as describedabove, and, in addition, allows the sensing unit to be mounted theretoin a simple structure.

SUMMARY OF THE INVENTION

Therefore, the present invention has been made to solve the aboveproblems, and other technical problems that have yet to be resolved.

Specifically, it is an object of the present invention to provide amiddle- or large-sized battery module to which a sensing unit that iscapable of minimizing the weight and size of battery cells whileeffectively reinforcing the low mechanical strength of the battery cellsand sensing the operation state of the battery cells is easily mounted.

It is another object of the present invention to provide a middle- orlarge-sized battery module that is manufactured by a simple assemblyprocess without using a plurality of members for mechanical coupling andelectrical connection, whereby the manufacturing costs of the middle- orlarge-sized battery module are lowered, and that is effectivelyprevented from being short-circuited or damaged during the manufactureor the operation of the middle- or large-sized battery module.

It is a further object of the present invention to provide a middle- orlarge-sized battery system that is manufactured using the middle- orlarge-sized battery module as a unit body such that the middle- orlarge-sized battery system has desired output and capacity.

In accordance with one aspect of the present invention, the above andother objects can be accomplished by the provision of a middle- orlarge-sized battery module comprising: a battery cell stack including aplurality of battery cells or unit modules electrically connected witheach other, the battery cells or unit modules being erected in thelateral direction; a first module case constructed in a structure toentirely surround one side end of the battery cell stack and topartially surround the upper and lower ends of the battery cell stack,the first module case being provided at the front part thereof withexternal input and output terminals; a second module case coupled withthe first module case, the second module case being constructed in astructure to entirely surround the other side end of the battery cellstack and to partially surround the upper and lower ends of the batterycell stack, the second module case being provided at the front partthereof with bus bars for connecting electrode terminals of the batterycell stack to the external input and output terminals; a sensing membermounted to the first module case or the second module case; and abattery management system (BMS) mounted to the first module case or thesecond module case, while being connected to the sensing member, formonitoring and controlling the operation of the battery module.

In the middle- or large-sized battery module according to the presentinvention, the battery cell stack is fixed to the first and secondmodule cases, and the sensing member and the BMS are mounted on themodule cases. Consequently, a process for assembling the battery moduleis simple, and the battery module is constructed in a simple and compactstructure.

In a preferred embodiment, the middle- or large-sized battery modulecomprises:

-   -   (a) a battery cell stack including a plurality of battery cells        or unit modules connected in series with each other, the battery        cells or unit modules being erected in the lateral direction;    -   (b) an upper case constructed in a structure to entirely        surround one side end of the battery cell stack and to partially        surround the upper and lower ends of the battery cell stack, the        upper case being provided at the front part thereof with        external input and output terminals;    -   (c) a lower case coupled with the first module case, the second        module case being constructed in a structure to entirely        surround the other side end of the battery cell stack and to        partially surround the upper and lower ends of the battery cell        stack, the lower case being provided at the front part thereof        with bus bars for connecting electrode terminals of the battery        cell stack to the external input and output terminals;    -   (d) a sensing member including sensing parts mounted in spaces        defined on the front and rear parts of the lower case and a        conduction part for interconnecting the sensing parts;    -   (e) a front cover mounted to the front part of the lower case        for protecting connections between the electrode terminals of        the battery cells and the bus bars from the outside, the front        cover being made of an insulative material; and    -   (f) a battery management system (BMS) mounted to the rear part        of the lower case, while being connected to the sensing member,        for monitoring and controlling the operation of the battery        module.

As described above, the battery cell stack is mounted in the cases insuch a manner that the plurality of battery cells or unit modules areerected in lateral direction. In the specification, regions of thebattery cells or the unit modules where the electrode terminals of thebattery cells or the unit modules protrude are defined as front and reardirections, and the opposite side edges of the battery cells or the unitmodules are defined as a lateral direction. Consequently, the batterycell stack is constructed in a structure in which the battery cells orthe unit modules are erected such that one of the side edges of thebattery cells or the unit modules is erected with respect to the groundwhile the electrode terminals of the battery cells or the unit modulesare oriented in the front and rear directions of the battery module.

Preferably, the battery cell stack comprises a plurality of unit moduleseach including plate-shaped battery cells having electrode terminalsformed at the upper and lower ends thereof. Each unit module comprisestwo or more battery cells constructed in a stacked structure in whichelectrode terminals of the battery cells are connected in series witheach other and the electrode terminal connections are bent such that thebattery cells are stacked, and a pair of high-strength cell covers forsurrounding the outer surfaces of the battery cells excluding theelectrode terminals of the battery cells when the cell covers arecoupled with each other.

The plate-shaped battery cells are secondary batteries having a smallthickness and a relatively large width and length, such that the totalsize of the secondary batteries is minimized when the secondarybatteries are stacked to construct a battery module. In a preferredembodiment, each plate-shaped battery cell is a secondary batteryconstructed in a structure in which an electrode assembly is mounted ina battery case made of a laminate sheet including a resin layer and ametal layer, and electrode terminals protrude from upper and lower endsof the battery case. Specifically, each battery cell is constructed in astructure in which the electrode assembly is mounted in a pouch-shapedbattery case made of an aluminum laminate sheet. Hereinafter, thesecondary battery with the above-stated construction will be referred toas a pouch-shaped battery cell.

The case of the pouch-shaped battery cell may be constructed in variousstructures. For example, the case of the pouch-shaped battery may beconstructed in a structure in which the electrode assembly is receivedin a receiving part formed at the upper inner surface and/or the lowerinner surface of a two-unit member, and the upper and lower contactregions are sealed.

The electrode assembly comprises cathodes and anodes, by which thecharge and the discharge of the battery are possible. The electrodeassembly may be constructed in a structure in which the cathodes and theanodes are stacked while separators are disposed respectively betweenthe cathodes and the anodes. For example, the electrode assembly may beconstructed in a jelly-roll type structure, a stacking type structure,or a stacking/folding type structure. The cathodes and the anodes of theelectrode assembly may be constructed such that electrode taps of thecathodes and electrode taps of the anodes directly protrude outward fromthe battery. Alternatively, the cathodes and the anodes of the electrodeassembly may be constructed such that the electrode taps of the cathodesand the electrode taps of the anodes are connected to additional leads,and the leads protrude outward from the battery.

The battery cells are surrounded, one by one or two by two, by thehigh-strength cell covers made of synthetic resin or metal so as toconstitute a unit module. The high-strength cell covers restrain therepetitive expansion and contraction change of the battery cells duringthe charge and discharge of the battery cells while protecting thebattery cells having low mechanical strength, thereby preventingseparation between sealing regions of the battery cells. Consequently,it is possible to manufacture a middle- or large-sized battery modulehaving further improved safety.

The battery cells are connected in series and/or parallel with eachother in one unit module, or the battery cells of one unit module areconnected in series and/or parallel with the battery cells of anotherunit module. In the preferred embodiment as described above, a pluralityof unit modules are manufactured by coupling electrode terminals of thebattery cells to each other, while arranging the battery cells in seriesin the longitudinal direction, such that the electrode terminals of thebattery cells are successively adjacent to each other, bending thebattery cells by twos or more such that the battery cells are stackedwhile being in tight contact with each other, and surrounding thestacked battery cells by predetermined numbers with the cell covers.

The coupling between the electrode terminals is accomplished in variousmanners, such as welding, soldering, and mechanical coupling.Preferably, the coupling between the electrode terminals is accomplishedby welding.

The battery cell stack, in which the battery cells are stacked in highintegration while the electrode terminals of the battery cells areconnected with each other, is vertically mounted in the separable upperand lower cases that are coupled with each other in the assembly-typecoupling structure.

Preferably, the upper and lower cases are constructed in a structure tosurround the edge of the battery cell stack and expose the outersurfaces of the battery cell stack to the outside so as to accomplisheasy heat dissipation of the battery cell stack when the upper and lowercases are coupled with each other after the battery cell stack ismounted in the upper and lower cases. Consequently, as described above,the upper case is constructed in a structure to entirely surround oneside end of the battery cell stack and to partially surround the upperand lower ends of the battery cell stack, and the lower case isconstructed in a structure to entirely surround the other side end ofthe battery cell stack and to partially surround the upper and lowerends of the battery cell stack.

In a preferred embodiment, the upper and lower cases are provided in theinsides thereof with pluralities of mounting grooves in which the edgesof the battery cells or the unit modules are inserted.

When the battery cell stack includes a plurality of unit modules, thecell covers of the unit modules are provided at the outer surfacesadjacent to the upper and lower ends thereof with steps of apredetermined size for easily fixing the unit modules, and the cellcovers are provided at the outer surfaces adjacent to the opposite sidesthereof with steps of a predetermined size for easily fixing the unitmodules, such that the battery cell stack is stably mounted to the casesand the unit modules are stacked while being in tighter contact witheach other, whereby the overall size of the battery cell stack isreduced. The mounting grooves of the upper and lower cases areconstructed in a structure corresponding to the steps.

Consequently, the steps formed adjacent to the edges of the unit modulesare inserted in the mounting grooves of the upper and lower cases,whereby a very stable coupling structure is formed even though only theedges of the unit modules are fixed to the cases.

Preferably, the lower case is provided at the insides of the front andrear parts thereof with pluralities of fixing grooves in which theelectrode terminal connections of the battery cells are inserted.Consequently, it is possible to prevent the battery cell stack frommoving forward and rearward and to maintain stable insulation betweenthe neighboring electrode terminal connections.

Preferably, the lower case is provided at the front part thereof with apair of slits through which the outermost electrode terminals of thebattery cell stack are inserted. When the battery cell stack is mountedto the lower case, the outermost electrode terminals of the battery cellstack are exposed through the slits and then bent such that theoutermost electrode terminals of the battery cell stack are brought intotight contact with the front part of the lower case. Consequently, theoutermost electrode terminals of the battery cell stack are more easilyconnected to the bus bars located at the front part of the lower case.

According to circumstances, a conductive member may be further mountedto at least one of the external input and output terminals for fixingthe upper end of the front cover and assisting with the connection of apower cable necessary for electrical connection. Each conductive membermay include bent parts for elastically surrounding the power cable. Inaddition, the front cover may be provided with holes for fixing thepower cable. Insulative coupling members are inserted through thecorresponding fixing holes such that the insulative coupling members arecoupled with some of the power cable.

Preferably, the front cover is coupled to the lower case in an assemblycoupling fashion.

The upper and lower cases are coupled with each other by mounting thebattery cell stack to one of the upper and lower cases (for example, thelower case) and coupling the other case (for example, the upper case) tothe frame member in which the battery cell stack is mounted. Thecoupling between the upper and lower cases may be accomplished invarious manners. For example, screws may be threadedly inserted intothread grooves formed at the opposite sides of the cases. Alternatively,a hook may be formed at one of the cases, and a coupling holecorresponding to the hook may be formed in the other case, whereby thecoupling between the upper and lower cases is accomplished without usingan additional coupling member.

Preferably, the lower case is provided at the lower end of the frontand/or rear part thereof with a coupling part which protrudes from thelower case and has a through-hole in the center thereof such that thelower case is fixed to an external device.

More preferably, the coupling part formed at the lower end of the frontor rear part of the lower case includes a pair of protruding couplingparts constructed such that one of the protruding coupling parts ishigher by a height equivalent to the thickness of the other protrudingcoupling part than the other protruding coupling part. Consequently,when a middle- or large-sized battery system is manufactured using aplurality of battery modules, it is possible to easily accomplish thecoupling between the battery modules and to construct the battery systemin a compact structure.

In a battery module including a plurality of battery cells, on the otherhand, it is necessary to measure and control the voltage and temperatureof the battery cells in consideration of the safety and operationalefficiency of the battery module. Especially, it is necessary to measurethe voltage of the respective battery cells or the respective electricalconnection regions of the battery cells. For this reason, the attachmentof a sensing member for measuring the voltage or temperature of thebattery cells is one of the principal factors further complicating theconstruction of the battery module.

The above-mentioned problem may be solved by the provision of a sensingmember mounted along one of the cases, i.e., the upper case or the lowercase, for sensing the voltage and/or temperature of the battery cells inaccordance with the present invention. Specifically, as described above,the sensing member includes sensing parts mounted in spaces defined onthe front and rear parts of the lower case and a conduction part forinterconnecting the sensing parts. The sensing member may be a voltagesensing member and/or a temperature sensing member.

In a preferred embodiment, the sensing parts of the voltage sensingmember are mounted in the front and rear parts of the lower case. Thesensing parts mounted in the rear part of the lower case may be directlyconnected to the BMS mounted to the rear part of the lower case, and thesensing parts mounted in the front part of the lower case may beconnected to the BMS via the conduction part mounted to the bottom ofthe lower case.

In another preferred embodiment, the sensing member includes thermistorsmounted to the battery cells or unit modules of the battery cell stack.The thermistors are connected to the BMS.

On the other hand, the lower case may be provided at the rear partthereof with a protruding BMS receiving part in which the BMS isintegrally assembled, preferably the BMS is received. The BMS receivingpart may be provided with a thermistor connector and a communicationconnector.

When a plurality of battery modules are used to construct a middle- orlarge-sized battery system, as described above, BMSs mounted to therespective battery modules may be said to be ‘slave BMSs.’

The middle- or large-sized battery module according to the presentinvention is constructed in a compact structure, and the mechanicalcoupling and electrical connection of the middle- or large-sized batterymodule are stably accomplished without using a plurality of members.Also, it is possible to construct a battery module using a predeterminednumber of battery cells, for example, four, six, eight, or ten batterycells, thereby effectively mounting a necessary number of batterymodules in a limited space.

In accordance with another aspect of the present invention, there isprovided a middle- or large-sized battery system having high output andlarge capacity, the battery system being constructed by connecting aplurality of battery modules.

The middle- or large-sized battery system according to the presentinvention may be manufactured by combining unit modules based on desiredoutput and capacity. The battery system according to the presentinvention is preferably used in all kinds of devices using electricpower, such as electric vehicles, hybrid electric vehicles, electricmotorcycles, and electric bicycles, which have a limit installationspace and are exposed to frequent vibration and strong impact inconsideration of the installation efficiency and structural stability ofthe battery system.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and other advantages of thepresent invention will be more clearly understood from the followingdetailed description taken in conjunction with the accompanyingdrawings, in which:

FIG. 1 is a perspective view illustrating a conventional representativepouch-shaped battery;

FIG. 2 is a perspective view illustrating a cell cover constituting aunit module according to a preferred embodiment of the presentinvention;

FIG. 3 is a perspective view illustrating a battery cell stack includinga plurality of unit modules;

FIG. 4 is an exploded perspective view illustrating upper and lowercases and a front cover of a middle- or large-sized battery moduleaccording to a preferred embodiment of the present invention;

FIGS. 5 and 6 are partial plan views respectively illustrating the frontand rear parts of the middle- or large-sized battery module according tothe present invention when unit modules are mounted to the lower case ofthe middle- or large-sized battery module;

FIGS. 7 to 10 are perspective views illustrating a voltage sensingmember used in the middle- or large-sized battery module according tothe present invention and how to mount the voltage sensing member to thebattery module;

FIGS. 11 and 12 are perspective views illustrating partially assembledstates of the middle- or large-sized battery module according to thepresent invention; and

FIG. 13 is a perspective view illustrating the assembly of a middle- orlarge-sized battery system according to a preferred embodiment of thepresent invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Now, preferred embodiments of the present invention will be described indetail with reference to the accompanying drawings. It should be noted,however, that the scope of the present invention is not limited by theillustrated embodiments.

FIG. 2 is a perspective view illustrating a cell cover constituting aunit module according to a preferred embodiment of the presentinvention.

Referring to FIG. 2, the cell cover 200 serves to supplement themechanical strength of two pouch-shaped battery cells, one of which isillustrated in FIG. 1, by mounting the battery cells therein and toallowing the battery cells to be easily mounted to a module case (notshown). The two battery cells are bent while one-side electrodeterminals of the battery cells are connected in series with each other,and are then mounted in the cell cover 200 while the battery cells arein tight contact with each other.

The cell cover 200 includes a pair of cover members 210 and 220 whichare coupled with each other. The cover members 210 and 220 are made of ahigh-strength metal sheet. At the opposite sides of the cell cover 200are formed steps 230, by which the module is easily fixed. At the upperand lower ends of the cell cover 200 are also formed steps 240 havingthe same function as the steps 230. In addition, fixing parts 250 areformed at the upper and lower ends of the cell cover 200 such that thefixing parts 250 extend in the lateral direction. The cell cover 200 iseasily mounted to the module case by the provision of the fixing parts250.

The cell cover 200 is provided at the outer surface thereof with aplurality of linear protrusions 260 which are spaced apart from eachother in the longitudinal direction. A protrusion 261 formed at themiddle of the cell cover has a depression 262, in which a thermistor(not shown) is mounted. Among the linear protrusions 260, the upper-endand lower-end protrusions have projection parts 263 and 264 formed inopposite shapes.

FIG. 3 is a perspective view illustrating a battery cell stack 300including a plurality of unit modules.

Referring to FIG. 3, the battery cell stack 300 includes four unitmodules 200 and 201. Two battery cells (not shown) is mounted in eachunit module 200. Consequently, a total of eight battery cells areincluded in the battery cell stack 300. Electrode terminals of theneighboring battery cells are connected in series with each other, andelectrode terminals of the neighboring unit modules are also connectedin series with each other. Electrode terminal connections 310 are bentin the sectional shape of a ‘[’ to construct the battery cell stack.Outside electrode terminals 320 and 321 of the outermost unit modules200 and 201 are bent inward in the sectional shape of a ‘.rightbrkt-bot.’ such that the electrode terminals 320 and 321 protrudeslightly more than the electrode terminal connections 310.

FIG. 4 is an exploded perspective view illustrating upper and lowercases and a front cover of a middle- or large-sized battery moduleaccording to a preferred embodiment of the present invention.

Referring to FIG. 4, the upper case 400 is constructed in a structure toentirely surround one side end of the battery cell stack as shown inFIG. 3 and to partially surround the upper and lower ends of the batterycell stack. The upper case 400 is provided at the front part 410 thereofwith a pair of external input and output terminals 420.

The lower case 500 is constructed in a structure to entirely surroundthe other side end of the battery cell stack and to partially surroundthe upper and lower ends of the battery cell stack. The lower case 500is coupled with the upper case 400. The lower case 500 is provided atthe front part 510 thereof with a pair of bus bars 520 for connectingelectrode terminals of the battery cell stack to the external input andoutput terminals 420. Specifically, the upper and lower cases 400 and500 are constructed in a structure in which, when the upper and lowercases 400 and 500 are coupled with each other, the upper and lower cases400 and 500 surround only the edge of the battery cell stack (notshown), such that the outer surface of the battery cell stack is exposedto the outside, so as to accomplish easy heat dissipation of the batterycell stack.

The upper end of each bus bar 520 is formed in the shape of a depressionsuch that the external input and output terminals 420 provided at thefront part 410 of the upper case 400 are inserted into the depressionsof the bus bars 520 when the upper and lower cases 400 and 500 arecoupled with each other.

In the insides of the upper case 400 and the lower case 500 are formedpluralities of mounting grooves 530 in which the edges of the batterycells or the unit modules are inserted. The mounting grooves 530 areconstructed in a structure in which the steps of the unit modules asshown in FIG. 2 are fitted in the corresponding mounting grooves 530.

Also, the upper case 400 and the lower case 500 are provided withpluralities of through-holes 430 and 532, through which a coolant(normally, air) flows, respectively, whereby effective cooling isaccomplished while the battery cell stack is mounted in the upper case400 and the lower case 500.

To the front part 510 of the lower case 500 is mounted a front cover 600for protecting connections between the electrode terminals of thebattery cells and the bus bars from the outside. The front cover 600 ismade of an insulative material.

To the external input and output terminals 420 are further mountedconductive members 440 for fixing the upper end of the front cover 600and assisting with the connection of a power cable (not shown) necessaryfor electrical connection.

For easy understanding, the conductive members 440 are shown to beseparated from the external input and output terminals 420 and locatedin front of the bus bars 520 in the drawing. Each conductive member 440is provided at one side thereof with a coupling insertion hole throughwhich the corresponding external input and output terminal 420 isinserted. Also, each conductive member 440 includes a pair of bent partsfor elastically surrounding the power cable.

The front cover 600 is provided with fixing holes 610 for fixing thepower cable. Insulative coupling members (not shown) are insertedthrough the corresponding fixing holes 610 such that the insulativecoupling members are coupled with some of the power cable.

The lower case 500 is provided at the front part 510 thereof with a pairof slits 522 which are formed at the right and left sides of the frontpart 510 of the lower case 500 such that the outermost electrodeterminals (not shown) of the battery cell stack are inserted through thecorresponding slits 522. When the battery cell stack is mounted to thelower case 500, the outermost electrode terminals of the battery cellstack are exposed through the slits 522 and then bent such that theoutermost electrode terminals of the battery cell stack are brought intotight contact with the front part 510 of the lower case 500.Consequently, the outermost electrode terminals of the battery cellstack are more easily connected to the bus bars 520 located at the frontpart 510 of the lower case 500.

FIGS. 5 and 6 are partial plan views respectively illustrating the frontand rear parts of the middle- or large-sized battery module according tothe present invention when unit modules are mounted to the lower case ofthe middle- or large-sized battery module.

Referring to these drawings, the lower case 500 is provided at theinsides of the front part 510 and the rear part 540 thereof withpluralities of fixing grooves 550 in which the electrode terminalconnections 310 of the unit modules 200 and electrode terminalconnections 310 of the battery cells mounted in the respective unitmodules 200 are inserted. The fixing grooves 550 are formed in a shapecorresponding to the electrode terminal connections 310 and 270.Consequently, the fixing grooves 550 prevent the battery cell stack 300from moving forward and rearward and maintain stable insulation betweenthe neighboring electrode terminal connections. Specifically, a cellcover movement preventing protrusion 552, a cell cover fixing guide 554,and an electrode terminal isolation wall 556 are formed in each fixinggroove 550 for accomplishing more stable fixing and insulation of theunit modules 200.

Also, the lower case 500 is provided at the lower end of the front partthereof with a coupling part 560 which protrudes from the lower case 500and has a through-hole 562 in the center thereof such that the lowercase 500 is fixed to an external device (not shown).

Especially, a protruding coupling part 570 formed at the lower end ofthe rear part of the lower case 500 includes a pair of opposite couplingparts 572 and 574. The coupling part 572 is formed such that thecoupling part 572 is higher by a height equivalent to the thickness ofthe coupling part 574 than the coupling part 574. Consequently, when amiddle- or large-sized battery system is manufactured using a pluralityof battery modules, the coupling between the battery modules is easilyaccomplished, and the battery system is manufactured in a compactstructure. The detailed structure of the protruding coupling part 570 isshown in FIG. 12.

At the rear part 540 of the lower case 500 is mounted a batterymanagement system (BMS) 600. The BMS 600 is received in a BMS receivingpart 580 integrally formed at the lower case 500. A thermistor connector582 and a communication connector 584 are mounted at the BMS receivingpart 580.

FIGS. 7 to 10 are perspective views illustrating a voltage sensingmember used in the middle- or large-sized battery module according tothe present invention and how to mount the voltage sensing member to thebattery module.

Referring to these drawings, the voltage sensing member 700 includes apair of supporting parts 710 and 712 mounted to the bottom of thebattery module 800 at regions corresponding to the electrode terminalconnections 310 of the battery cells or the unit modules, a wire-shapedconduction part 720 for electrically interconnecting the supportingparts 710 and 712, pluralities of conductive compression springs 730each having one end fixed to the corresponding support part 710 or 712and the other end elastically connected to the corresponding electrodeterminal connection 310, a BMS 600 mounted on the rear supporting part712, and a connector 584.

The voltage sensing member 700 with the above-described construction ismounted to the front part 510, the rear part 540, and the bottom 590 ofthe lower case 500 in an insertion fashion. Consequently, the batterymodule 800 is easily assembled and constructed in a stable structure.

FIGS. 11 and 12 are perspective views illustrating partially assembledstates of the middle- or large-sized battery module according to thepresent invention.

Referring to these drawings, the battery module 800 is easily assembledby the coupling between the upper and lower case 400 and 500. The BMS(not shown) is received in the BMS receiving part 580 integrally formedat the rear part 540 of the lower case 500. Consequently, the batterymodule 800 is constructed in a simple and compact structure. Also, twoor more battery modules may be connected with each other by the couplingbetween the pair of coupling parts 572 and 574 formed at the lower endof the rear part 540 of the lower case 500 such that the pair ofcoupling parts 572 and 574 have different heights.

FIG. 13 is a perspective view illustrating the assembly of a middle- orlarge-sized battery system according to a preferred embodiment of thepresent invention.

Referring to FIG. 13, the middle- or large-sized battery system 900 isconstructed in a structure in which a plurality of battery modules 800and 801, one of which is shown in FIG. 12, are mounted on a frame 910,and the battery modules 800 and 801 are connected to anelectric/electronic subassembly 930 located at one side of the frame 910via a power cable (partially shown) 920.

The electric/electronic subassembly 930 includes a master BMS connectedto BMSs (not shown), i.e., slave BMSs, of the respective battery modules800 and 801 for controlling the slave BMSs and various kinds ofelectric/electronic devices for controlling the overcharge,overdischarge, and overcurrent of the battery system 900 and input andoutput of power.

The battery modules 800 and 801 are stably fixed to the frame 910 by thecoupling part 560 and opposite supporting members 940 and 942, andtherefore, the battery system is structurally stable when externalimpart is applied to the battery system.

Although the preferred embodiments of the present invention have beendisclosed for illustrative purposes, those skilled in the art willappreciate that various modifications, additions and substitutions arepossible, without departing from the scope and spirit of the inventionas disclosed in the accompanying claims.

INDUSTRIAL APPLICABILITY

As apparent from the above description, the present invention has theeffect of easily mounting a sensing unit that is capable of minimizingthe weight and size of battery cells while effectively reinforcing thelow mechanical strength of the battery cells and sensing the operationstate of the battery cells to a middle- or large-sized battery module.In addition, the present invention has the effect of manufacturing thebattery module by a simple assembly process without using a plurality ofmembers for mechanical coupling and electrical connection, therebydecreasing the manufacturing costs of the battery module, andeffectively preventing the battery module from being short-circuited ordamaged during the manufacture or the operation of the battery module.Furthermore, the present invention has the effect of manufacturing amiddle- or large-sized battery system having desired output and capacityusing the battery module as a unit body.

1. (canceled)
 2. A middle- or large-sized battery module comprising: abattery cell stack including a plurality of unit modules electricallyconnected with each other, wherein each unit module includes two or morebattery cells constructed in a stacked structure in which electrodeterminals of the battery cells are electrically connected with eachother and electrode terminal connections are bent such that the batterycells are stacked; a first module case configured to surround a side endof the battery cell stack and to partially surround upper and lower endsof the battery cell stack, the first module case being provided at afront part thereof with external input and output terminals; a secondmodule case coupled with the first module case, the second module caseconfigured to surround another side end of the battery cell stack and topartially surround the upper and lower ends of the battery cell stack,the second module case being provided at a front part thereof with busbars for connecting electrode terminals of the battery cell stack to theexternal input and output terminals; and a sensing member mounted to thefirst module case or the second module case.
 3. The battery moduleaccording to claim 2, wherein the plurality of unit modules areconnected in series; wherein the sensing member includes sensing partsmounted in spaces defined on the front part and a rear part of thesecond module case and a conduction part for interconnecting the sensingparts; and wherein the battery module further comprises a front covermounted to the front part of the second module case for protectingconnections between the electrode terminals of the battery cell stackand the bus bars, the front cover being made of an insulative material.4. The battery module according to claim 3, wherein the battery cellsare plate-shaped battery cells having the electrode terminals formed atupper and lower ends thereof, and the electrode terminals of the batterycells are connected in series with each other, and a pair ofhigh-strength cell covers for surrounding outer surfaces of the batterycells excluding the electrode terminals of the battery cells when thecell covers are coupled with each other.
 5. The battery module accordingto claim 4, wherein the cell covers are provided at outer surfacesthereof adjacent to upper and lower ends thereof with first steps of apredetermined size for easily fixing the unit modules, and the cellcovers are provided at the outer surfaces thereof adjacent to oppositesides thereof with second steps of a predetermined size for easilyfixing the unit modules, the mounting grooves of the first and secondmodule cases configured to correspond with the first and second steps.6. The battery module according to claim 2, wherein the first and secondmodule cases are provided in insides thereof with pluralities ofmounting grooves in which edges of the unit modules are inserted.
 7. Thebattery module according to claim 6, wherein the cell covers areprovided at outer surfaces thereof adjacent to upper and lower endsthereof with first steps of a predetermined size for easily fixing theunit modules, and the cell covers are provided at the outer surfacesthereof adjacent to opposite sides thereof with second steps of apredetermined size for easily fixing the unit modules, the mountinggrooves of the first and second module cases configured to correspondwith the first and second steps.
 8. The battery module according toclaim 4, wherein the second module case is provided at insides of thefront and rear parts thereof with pluralities of fixing grooves in whichthe electrode terminal connections are inserted.
 9. The battery moduleaccording to claim 4, wherein the second module case is provided at thefront part thereof with a pair of slits through which the outermostelectrode terminals of the battery cell stack are inserted.
 10. Thebattery module according to claim 9, wherein the outermost electrodeterminals of the battery cell stack are inserted through the slits andthen bent such that the outermost electrode terminals are connected tothe bus bars located at the front part of the second module case. 11.The battery module according to claim 3, wherein an upper end of eachbus bar is formed in a shape of a depression such that the externalinput and output terminals provided at the front part of the firstmodule case are inserted into the depressions of the bus bars when thefirst and second module cases are coupled with each other.
 12. Thebattery module according to claim 3, further comprising: a conductivemember mounted to at least one of the external input and outputterminals for fixing an upper end of the front cover and assisting withconnection of a power cable necessary for electrical connection.
 13. Thebattery module according to claim 3, wherein the front cover is coupledto the second module case in an assembly coupling fashion.
 14. Thebattery module according to claim 3, wherein the front cover is providedwith holes for fixing a power cable.
 15. The battery module according toclaim 3, wherein the second module case is provided at a lower end of(i) the front part thereof, (ii) the rear part thereof, or (iii) boththe front and rear parts thereof with a coupling part which protrudesfrom the second module case and has a through-hole in a center thereofsuch that the second module case is fixed to an external device.
 16. Thebattery module according to claim 15, wherein the coupling part includesa pair of protruding coupling parts constructed such that one of theprotruding coupling parts is higher by a height equivalent to athickness of the other protruding coupling part than the otherprotruding coupling part.
 17. The battery module according to claim 2,further comprising: thermistors mounted to the unit modules of thebattery cell stack.
 18. A middle- or large-sized battery systemcomprising a plurality of battery modules, wherein each battery modulecomprises: a battery cell stack including a plurality of unit moduleselectrically connected with each other, wherein each unit moduleincludes two or more battery cells constructed in a stacked structure inwhich electrode terminals of the battery cells are electricallyconnected with each other and electrode terminal connections are bentsuch that the battery cells are stacked; a first module case configuredto surround a side end of the battery cell stack and to partiallysurround upper and lower ends of the battery cell stack, the firstmodule case being provided at a front part thereof with external inputand output terminals; a second module case coupled with the first modulecase, the second module case configured to surround another side end ofthe battery cell stack and to partially surround the upper and lowerends of the battery cell stack, the second module case being provided ata front part thereof with bus bars for connecting electrode terminals ofthe battery cell stack to the external input and output terminals; and asensing member mounted to the first module case or the second modulecase; wherein the battery system further comprises a battery managementsystem connected to the battery modules for monitoring and controllingoperation of the battery modules.
 19. An electric vehicle including thebattery system according to claim 18 as a power source.
 20. A hybridelectric vehicle including the battery system according to claim 18 as apower source.